Bring water, Shiso Teriyaki, garlic and ginger to the boil. Simmer for 5 minutes. Add the katsuobushi, turn off the heat and leave for 10 minutes. Finely strain into a seperate bowl, and add the ponzu. Cook soba, or your preferred noodle, according to packet instructions. Divide the broth between two bowls, place in your cooked noodles, garnish with lime and prawns.